The conventional technology discloses a patent on an Openflow based communication technique for implementing SDN and a patent on technology for transmitting traffic based on the Openflow after placing an EPC on a cloud in an LTE network.
U.S. Ser. No. 13/176,619, Openflow Communication System and Openflow Communication Method, Kiyohisa Ichino (NEC Corporation)
U.S. Ser. No. 13/536,838, Implementing EPC in a Cloud Computer with Openflow Data Plane, James Kempf, et al. (Telefonaktiebolaget LM Ericsson).
Software-Defined Networking (SDN) is a technology that separates a control plane and a data plane and concentrates the control plane on a single controller. In the SDN scheme, the data plane is simply in charges of traffic forwarding, and information on where to and how to transfer traffic is determined by a central controller. In particular, the controller provides various APIs through a northbound API and enables programming using the various APIs to perform various traffic controls based on network information. An Openflow protocol can be a protocol that supports the SDN to operate, and is also referred to as a southbound protocol that transfers forwarding information between the controller and a switch and that transfers a state of a switch or traffic information, etc. to the controller.
The first patent relates to an Openflow technology and generally discloses an operation of Openflow and an operation method in a switch to which Openflow is applied. The second patent relates to a method for implementing the EPC in the cloud. As a method for implementing the EPC in the cloud, proposed is a method for separating the control plane and data plane, implementing the control plane in the cloud, additionally executing the control function within the cloud when a virtualized control function is further needed depending on the traffic load, and then realizing the interworking of the data plane and the control plane using an openflow technique.
The present invention proposes the following three examples of the services performed in the SDN-based LTE Network. The first is for interworking with the cache installed in the eNB, the second is for VoLTE traffic transmission, and the third is for a 1:N media sharing service. A previous study carried out for each is as follows.
An operation of the prior art with respect to an access cache and a core cache that provide a content caching function in an eNB and a core is described in the following. If the UE requests the content, an access cache located in an eNB site initially checks whether the same content is stored therein, and when the same content is stored, transmits the content to the UE. At this time, a method for transferring traffic can be different depending on a method for implementing the core cache and access cache. When using a technique referred to as byte caching, even if the content of the UE is stored in the access cache, in order to transmit the content to the UE by the access cache, it must be known which content is to be transmitted to the core cache. To this end, the access cache transmits a small packet referred to as a label to the core cache. The access cache receives the label, extracts a content corresponding to the label from the storage, makes the content into a packet, and transmits the packet to the UE. On the other hand, when using a technique called object caching, the access cache performs the role of a content source and directly transmits the content to the UE, and the core cache does not transfer the content to the UE.
A basic operation defined in the standard with respect to the VoLTE service is as follows. A transmission UE, which is trying to a call, transmits a voice packet to a network based on information of a reception UE. The voice packet is transmitted to the reception UE through an IMS located on top of the EPC and passes through the EPC again. The response of the reception UE is also transmitted through the same path.
A 1:N media sharing service means a personal broadcasting environment where a single UE can be a content providing source and a plurality of UEs may receive the content. In this case, the transmission UE requires a procedure of registering the content to be transferred by the transmission UE itself, and the reception UE should inform of the intention to receive the content to the server. Further, the content transmitted by the transmission UE is transferred to a media sharing server and copied and transferred to each of the reception UEs in a unicast transmission.